Numerous studies have attempted to measure scientists' influence by measuring the quantity of citations to their works. The problem with "citation counting," as it is called, is that it assumes that each listing of an author in a citation index is equal to another without bothering to explore the substantive uses of citations in the source article. The present study attempts to alleviate this problem by content analysis of citations in a limited sphere: reference to major philosophers of science by sociologists. In just over 100 sociology journals, citations to Thomas Kuhn, Karl Popper, Ernst Nagel, and Carl Hempel (overall, the most frequently cited philosophers of science) from 1971-1982 were randomly sampled. Each citation was classified according to the following criteria: 1) philosopher cited; 2) work cited, 3) exclusivity (whether cited with others); 4) multiplicity (number of citations by the philosopher in the same article); 5) type of article; and 6) purpose of citation. Purposes of citation included seven categories: 1) listing as relevant literature; 2) definition of a concept; 3) modification or extension of a philosopher's theory; 4) formulation of a research problem; 5) interpretation of results; 6) critical of philosopher's work; and 7) other. Analysis of these data …